A DC power supply device such as a motor driver, a DC-DC converter, and a power supply coupler circuit includes a high-side MOS transistor that converts an input voltage into an output voltage used to drive a load. As an example of such a DC power supply device including the high-side MOS transistor, a circuit has been proposed which generates an ON voltage for driving the high-side MOS transistor through a charging and boosting operation using a charge pump circuit and supplies the generated ON voltage (for example, see Patent Document 1).    Patent Document 1: JP 2007-214647 A